Where has all the Bitcoin gone? Research shows that 453,000 BTC have been confiscated by governments

The most important value proposition of Bitcoin should be anti-censorship. Simply put, if operated properly, no one can freeze or confiscate your Bitcoin. As long as you control the private key, you are the real holder of Bitcoin.
However, many Bitcoins are still confiscated; usually as a result of mishandling. According to research by TheBlock, the number of Bitcoins seized currently accounts for 2.6% of the total circulating supply.

(Image source: TheBlock)

Last week, it was reported that “many bitcoin analysts believe the U.S. government now controls more bitcoin than any other country in the world,” citing a December 2013 Wired magazine article.
At that time, the US government actually controlled about 174,000 bitcoins, which came from Ross Ulbricht, the founder of the dark web Silk Road. This part of the confiscated bitcoins accounted for 1.5% of the circulation at the time (it should be noted that before reaching the upper limit of 21 million, the circulation of bitcoins will continue to increase due to mining). But that was 5 years ago, and a lot has changed in the past few years.
First of all, it is absolutely impossible for the US government to hold a large amount of Bitcoin. The Bitcoins confiscated in the Silk Road case were divided into two batches. The first batch was auctioned in June 2014. It is well known that the buyer of these coins was Tim Draper, a well-known venture capitalist and cryptocurrency enthusiast. The second batch was auctioned in September last year and sold for $48.2 million.
I believe the US government still holds some Bitcoin, but it is definitely far less than before. According to TheBlock, the US government currently holds at least 4,100 BTC, but definitely no more than 10,000 BTC. The United States has seized about 198,000 BTC from at least 100 different federal criminal, civil and administrative cases. 98% of the Bitcoins were auctioned, totaling $151 million, which means that the average price of each Bitcoin is $780.

(Image source: TheBlock)

The largest Bitcoin confiscation case involving funds remains shrouded in mystery and controversy. On May 19 last year, the Southeast European Law Enforcement Center (SELEC) issued a press release stating that "the Bulgarian government has confiscated more than 200,000 Bitcoins worth $500 million."
Members of organized crime groups invested funds obtained from illegal activities into Bitcoin, and Bulgaria found about 200,000 Bitcoins in the virtual space.
However, in December last year, Ivan Geshev, the head of the Bulgarian Special Prosecutor's Office, said that "no bitcoins have ever been confiscated". It is very likely that SELEC failed to obtain the private key. It is also possible that there is corruption within its government. SELEC should at least disclose the address of these bitcoins.
If these 200,000 bitcoins are included, the number of confiscated bitcoins has reached nearly 453,000, or 2.6% of the total circulation. But it is worth noting that 85.6% of the bitcoins came from two cases: Silk Road and SELEC.
The confiscation of censorship-resistant Bitcoin has become the norm, but as operations become more standardized, such cases will become less and less common in the future.
The following is a list of publicly available records showing all Bitcoins that have been confiscated and auctioned for more than $500,000.